3A- Biomolecules

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A) HOMEOSTASIS
- The ability of the body or a cell to seek and maintain a condition of equilibrium or stability within its internal environment when dealing with external changes.
- e.g. of processes that help a living organism to maintain equilibrium: osmosis, diffusion, active and passive transport
- Important component in maintaining equilibrium: Cell Membrane

B) MATTER, ENERGY and ORGANISATION- Biomolecules

*Living systems are complex and highly organized, and they require matter and energy to maintain this organization.
  • Energy is stored in the organization of matter. (e.g. energy is stored in forms of carbohydrates/fats- storage systems)
  • Living organisms use matter and energy to build and maintain body structures. (e.g. food is converted into biomolecules (energy) that is used for various life processes and activities)
  • Living organisms obtain and process matter and energy (e.g. humans eat to get energy so that our body can function, our cells need glucose so that the mitochondria can generated ATP, for the cell to use)
  • The structure of a molecule always dictates its function. (e.g. phospholipids- hydrophyllic and hydrophobic end to form the cell membrane)
  • The structure and function of biological living systems obeys the laws of thermodynamics.
  • Communities of organisms depend on the cycling of matter and the flow of energy
  • The constant flow of energy and cycling of matter in the biosphere leads to a balanced or steady state.

This balance is achieved through various biogeochemical cycles and the processes of photosynthesis and cellular respiration - focus is on ENERGY

WHAT WE NEED TO KNOW AND QUESTION:
In order for us to understand this better, we will start by looking at biomolecules.
The questions we ask about ourselves and the world around us:

  1. Are we just chemicals?
  2. Are we what we eat?
  3. Why is the carbon molecule suitable for life as we know it?
  4. Why is the chemistry of water suitable for life?

In this unit you will need to know:
  • Understand and describe the properties of some important biological molecules; understand their roles, recall, recognize and identify the general formulae and structure of these molecules.
  • Water: understand its dipolar nature; understand formation of hydrogen bonds; understand the importance of water as a solvent; understand other roles of water related to its high latent heat of vapourisation, specific heat capacity, density and surface tension.
  • Lipids: understand the general nature of lipids as fats, oils and waxes; describe the roles of lipids as energy stores, and, in protection, waterproofing, insulation and buoyancy.
  • Proteins: understand the nature of amino acids as monomers in the formation of polypeptides and proteins; understand the meaning of the terms primary, secondary, tertiary and quaternary structure and their importance in the structure of enzymes; understand that condensation and hydrolysis reactions are involved in the synthesis of proteins; understand the nature and roles of fibrous and globular proteins as illustrated by collagen and (insulin?) hemoglobin.
  • Carbohydrates: understand that pentose and hexose’s are monosaccharide and have roles as monomers; understand that disaccharides and polysaccharides are composed of monomers joined by glycosidic bonds.; understand that condensation and hydrolysis reactions are involved in the synthesis and degradation of disaccharides and polysaccharides. Recall the structure and roles of basic carbohydrates.
  • Vitamins and minerals: understand their role and the effects of deficiency
  • Enzymes: understand the structure of enzymes as globular proteins, and the concept of active site and specifity; understand that enzymes are catalysts which reduce activation energy; understand how enzyme activity is affected by temperature, pH, substrate and enzyme concentrations; understand active site-directed and non-active site-directed inhibition of enzyme action; have an appreciation of the commercial uses of enzymes as illustrated by pectinases in food modification and proteases in biological detergents; discuss the advantages of immobalisation of commercial enzymes, as illustrated by lactase;